UL-Listed, non-actuated, dynamic fire dampers protect oversized openings in buildings. With fabricated steel 3V blade type, Model DFD-210 has max size of 128 x 100 in. and 1.5 hr fire resistance rating. Model DFD-230 has max size of 72 x 48 in. with 3 hr fire resistance rating, while Model DFDAF-310, which features fabricated steel airfoil blades, has max size of 128 x 100 in. and 1.5 hr fire resistance rating. With max size of 120 x 96 in., Model DFDAF-330 has 3 hr fire resistance rating.